A variety of analog meters are known, and widely used for measuring and recording the quantity or rate of flow of gas, electricity, or water passing through it, by means of the operation of a movement and a pointer. In recent years, analog meters have been gradually replaced by digital meters. However, a digital meter is relatively expensive, and may be interfered by outside noises or ambient conditions. Further, a digital indicator meter is not suitable for use in motor vehicles because it is difficult to realize the quantity or rate by a glance. When a figure, for example: 35 KM or 65 KM was read out, one must use brains to judge if such figure represents a low speed or high speed. The pointer of an analog meter directly indicates the amount of movement, and its movement can be easily seen even when the intensity of ambient light is low.
The movement of an analog meter may be made from moving coil, moving iron or air core, etc. according to its purpose. An air core movement, as shown in FIG. 1, is also known as "cross coils movement", which comprises a center shaft connected to a permanent magnet at the center mounted within two vertically connected bobbins, and two coils A and B wound round the bobbins. Coil A is equally wound round the bobbins at two opposite sides relative to the center shaft. Coil B is wound round the bobbins crossed over coil A and equally arranged at two opposite sides relative to the center shaft. During the winding of coils A and B, the bobbins may be caused to deform. If the coils A and B deform the bobbins, the center shaft may be stuck during the operation. Further, if the number of turns of either coil A or B is not equally distributed at two opposite sides relative to the center shaft and the tension of either coil A or B is not uniformly distributed, the total impedance of coils A and B will be different, thereby causing a indication error. This coil winding method can not get rid of the effect of outside temperature. Further, coil A produces a poor heat dissipating effect because it is covered within coil B, thereby resulting in an unbalanced impedance. When the impedance is unbalanced, the accuracy of the indication will be affected. Because the coil winding process is difficult to perform, the manufacturing speed is hindered. Because this conventional production method can not eliminate high defective rate, a lot of time will be spent on correction. Furthermore, the application of the bonding agent to fasten the ends of the wires greatly increases material and labor costs.
The present invention has been accomplished under the aforesaid circumstances. It is therefore the main object of the present invention to provide a detachable coils air core movement holder which is inexpensive to manufacture, and easy to assembly.